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50 Cards in this Set
- Front
- Back
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What is immunity? |
A biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion Involves both specific and non-specific components The nonspecific- components act either as barriers or as eliminators of wide range of pathogens irrespective antigenic specificity Other components of the immune system adapt themselves to each new ideas encountered and are able to generate pathogen-specific immunity |
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Host defenses: |
Innate nonspecific Acquired, specific; third line of defense |
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Innate nonspecific: |
First line of defense Second Line of defense |
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First line of defense: |
PCG Physical barriers, Chemical barriers, Genetic barriers is a surface protection composed of anatomical and physiological barriers that keep microbes from penetrating sterile body compartments. |
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Second line of defense: |
IIPC Inflammatory response, interferons, phagocytosis, Complement is a cellular and chemical system that comes immediately into play if infectious agents make it past the surface defenses. Examples include phagocytes that engulf foreign matter and destroy it, and inflammation which holds infections in check. |
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Acquired, specific; third line of defense |
Naturally acquired, Artificially acquired
includes specific host defenses that must be developed uniquely for each microbe through the action of specialized white blood cells. This form of immunity is usually long term and has memory. |
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Naturally Acquired: |
Active: infection
Passive: Maternal antibodies (Antibodies, T cells, accessory cells and cytokines) |
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Artificially Acquired: |
Active: Vaccination
Passive: Immune serum (Antibodies, T cells, accessory cells and cytokines) |
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Physical and chemical barriers:
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-physical
-skin -mucus membrane -mucus -cilia -reflexes -normal flora -genetic resistance specific differences individual differences -chemical -pH fatty acids on skin -lysozymes -proteases -stomach acid |
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The immune system: organs
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Lymphatic system
Spleen Thymus Other lymphoid tissue |
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Lymphatic system: |
Lymph nodes
----- houses immune cells |
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Spleen
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filters pathogens in the blood |
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Thymus: |
Site of T cell maturation |
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Other lymphoid tissue |
--GALT--gut associated lymphoid tissue -Peyer's patches- intestines |
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Immune cells in the blood: Whole blood contains: |
-Red blood cells -carry O2 and CO2
-White blood cells ---leukocytes -Plasma water proteins chemicals |
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Blood plasma contains: |
clotting factors complement antibodies molecules not related to defense |
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Serum is missing.... |
clotting proteins ---from clotted blood |
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Resistance to infectious disease |
Innate immunity adaptive immunity |
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Innate immunity |
nonspecific resistance protest us against all pathogens over-the-counter defenses |
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Adaptive immunity |
specific resistance defends against specific pathogens prescription defenses |
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Nonspecific host defense- Innate immunity: |
-Always present -immediately effective -no immune memory- work at the same speed each time |
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Inflammation: |
Triggered by tissue damage Rubor Calor Tumor Dolor |
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Rubor: |
redness ---from increased vascular permeability (more blood to the area) |
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Calor: |
warmth ---from the increase in blood |
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Tumor: |
swelling ---from the increased amount of fluids into the tissue |
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Dolor: |
pain ---from the stimulation of the nerve endings |
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Inflammation- injury and mediator release Presence of Bacteria... |
1. A cut penetrates the epidermis barrier, and bacteria invade. |
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2. Damages cells release prostaglandins, leukotrienes, and histamine |
3. Prostaglandins and leukotrienes make vessels more permeable. Histamine causes vasodilation, increasing blood flow to the site. |
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4. Macrophages and neutrophils squeeze through walls of blood vessels (diapedesis). |
5. Increased permeability allows antimicrobial chemicals and clotting proteins to seep onto damaged tissue but also results in swelling, pressure on nerve endings, and pain. |
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6. Blood clot forms 7. More phagocytes migrate to the site and devour bacteria 8. Accumulation of damaged tissue and leukocytes forms pus. |
9. Undifferentiated stem cells repair the damaged tissue. Blood clot is absorbed or falls off as a scab. |
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The process of phagocytosis: |
Phagocytosis = eating of cells |
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Neutrophils (aka PMNs) : |
are present in the highest numbers in blood |
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Macrophages ("big eaters") : |
in the tissues encounter the pathogen first.
--secrete cytokines ----> inflammation, systemic responses |
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Pathogen recognition molecules on phagocytes: |
membrane receptors (on phagocytes) bind commonly shared bacterial molecules -LPS (endotoxin, (Gram -) -Lipoteichoic acid ( Gram +) -Patterns of sugars (PAMPs- pathogen-associated molecular patterns) -nucleic acids |
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Pathogen recognition continued... Phagocyte must... |
bind pathogen to begin phagocytosis |
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Microbes with capsules are.... |
difficult to bind ---difficult to phagocytose |
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Phagocytosis is easier if the pathogen is... |
coasted with antibodies or complement (opsonins) |
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Macrophages produce chemokine to increase inflammation: |
This leads to --capillary leakiness --attracts more phagocytes: PMNs --increases adhesion molecules for PMNs on capillary endothelium |
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PMN Diapedesis: |
-Normal permeability -Increased permeability of venue during inflammation |
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Normal permeability |
Venues wall Small amount of fluid Monocyte Small amount of fluid |
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Increased permeability of venue during inflammation |
Interstitial spaces More fluid and antimicrobial chemicals Monocyte squeezing through interstitial space (diapedesis) More fluid |
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Macrophages produce lymphokines |
-Signals the adaptive immune system -Fluid contains the pathogen drains from infection site into nearby lymph nodes -Lymph nodes contain specific B and T cells ---make the adaptive immune response ---produce the immune memory cells |
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Macrophage lymphokines |
-Signal hypothalamus to increase body temperature = fever -Signal liver to produce acute phase proteins = opsonins that aid phagocyte binding of pathogen -Signal bone marrow to release more PMNs (neutrophils) |
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Pathogen destruction |
-Pathogen is killed by enzyme digestion, toxic oxygen molecules, and defense's -Some pathogens resist killing and live in phagosome or escape to cytosol (Mycobacterium tuberculosis, Listeria monocytogenes) |
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Two plasma protein defense systems : |
Complement -lyses bacteria Interferon- stops virus infection |
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Complement - classical pathway |
Initiation: --C1 binds to antibodies attache to a bacterium Amplification and cascade --C1 activates other components --some stimulate inflammation --some come together and begin to bind on the surface of the bacterium |
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Complement - classical pathway continued |
Polymerization: -more subunits come together and bind on the surface Membrane attack: -final product is an enzyme that blasts a hole in the bacterium's membrane |
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Anti-Viral interferons |
-IFNa (alpha) and IFNB (beta) made by virus-infected cells -not virus-specific -Bind neighboring host cells and induce synthesis of anti-viral proteins to block virus replication |
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Gamma interferon |
-IFNy (gamma) is made by T cells -Activates macrophages and neutrophils to kill bacteria - [ IFNy is not antiviral ] |
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Yet another defensive cell: Natural Killer Cells |
NK cells recognize virus-altered receptors and kill virus-infected cells (also tumor cells) -All nucleated cells in body have these membrane receptors -NK cells can "recognize" cells that are infected -Stimulate those cells to apoptose |
